Fat is bad for you, fat is good for you. Carbs are bad, but only refined carbs. Put pureed vegetables in your lasagna. Dietary advice is perennially confusing, but at least you know you should avoid salt, right? Yeah, no.

According to the Times, a new study has found that a low-salt diet increased the risk of heart disease death. Researchers tracked 3,681 middle-aged people who were healthy at the outset, for an average of about 8 years. They found that those who ate the least salt — as measured by the sodium content of their urine — were most likely to die of heart disease. And while those who ate the most salt had a small increase in blood pressure, they were not more likely to get hypertension.

This contradicts everything we've been told about salt previously — namely, that it will make your heart explode. And understandably, some experts are skeptical. Dr. Peter Briss of the CDC pointed out that the subjects who ate the least salt almost seemed to have the least urine — they could have been cheating by throwing away some of their salty pee. And, he says, the study involved too few heart attacks to be really conclusive. Also, the study was observational, and some say real conclusions about salt would require a randomized controlled trial. Says Briss, "At the moment, this study might need to be taken with a grain of salt." Lolz!

Advertisement

Seriously, the study is troubling because it highlights how little we know about what's good for us. A healthy diet is frequently touted as a way of preventing and even curing most diseases, ensuring a long and happy life. But it often seems we don't really know what a healthy diet is. And while many experts say we shouldn't be changing any dietary guidelines based on the salt study, the findings are a reminder that ideas about healthy eating are constantly evolving. And while we can make some guesses, that magic diet that keeps disease at bay remains essentially a pipe dream.